[Dúvida] Dúvida Exception

Fiz o exercício como a instrutora fez, mas não imprime, aparece essa exception. Por que??

Exception in thread "main" java.lang.NoClassDefFoundError: com/google/gson/GsonBuilder at br.com.screenmatch.principal.PrincipalComBusca.main(PrincipalComBusca.java:36) Caused by: java.lang.ClassNotFoundException: com.google.gson.GsonBuilder at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:641) at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:188) at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:520) ... 1 more

package br.com.screenmatch.principal;

import java.io.IOException; import java.net.URI; import java.net.http.HttpClient; import java.net.http.HttpRequest; import java.net.http.HttpResponse; import java.net.http.HttpResponse.BodyHandlers; import java.util.Scanner;

import com.google.gson.FieldNamingPolicy; import com.google.gson.Gson; import com.google.gson.GsonBuilder;

import br.com.screenmatch.modelos.Titulo; import br.com.screenmatch.modelos.TituloOmdb;

public class PrincipalComBusca {

public static void main(String[] args) throws IOException, InterruptedException {

    Scanner leitura = new Scanner(System.in);
    System.out.println("Digite um filme: ");
    String busca = leitura.nextLine();

    String endereco = "http://www.omdbapi.com/?t=" + busca + "&apikey=b560d051";

    HttpClient client = HttpClient.newHttpClient();
    HttpRequest request = HttpRequest.newBuilder().uri(URI.create(endereco)).build();

    HttpResponse<String> response = client.send(request, BodyHandlers.ofString());

    String json = response.body();
    System.out.println(json);

    Gson gson = new GsonBuilder().setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE).create();

    TituloOmdb meuTituloOmdb = gson.fromJson(json, TituloOmdb.class);
    System.out.println(meuTituloOmdb);
    Titulo meuTitulo = new Titulo(meuTituloOmdb);
    System.out.println(meuTitulo);

}

}